The proposal is to investigate behavioral effects on the phosphorylation of nuclear and synaptic proteins of brain. The methods involve separation of neurons from glia, and the isolation of nuclei from the separated cell populations. Phosphorylation of nuclear proteins will be studied in vitro by tracer methods in neurons and glia that have been prepared from trained and naive animals. In vivo experiments will be carried out in which radioactive orthophosphate will be administered prior to training, and then cell populations will be separated and nuclei isolated as described above. In either case, nuclear proteins from light and heavy chromatin fractions, and from nucleoli, will be separated by polyacrylamide gel electrophoresis, and examined for changes in isotope incorporation. Similar in vivo and in vitro experiments will be performed on synaptosome preparations from whole brain. Effects found by any of these approaches will be examined to determine the anatomical region of the brain that is involved. These effects will also be examined to see if they can be demonstrated, without the use of radioisotopes, by means of estimating changes in phosphoserine or phosphothreonine content of the proteins involved.